If you're headed to the Mall of America in the next two years — yes, that's years — brace yourself for delays and detours.

Work to prepare for the long-awaited second phase of expansion at the Bloomington megamall began in earnest this month, and already motorists are finding themselves surprised by signs of change.

Those who access the mall on Lindau Lane from Hwy. 77 will now find that shortly after leaving the highway, they have to turn left toward Ikea or right into the mall. Parts of Lindau will be closed until July 2014, though Bloomington officials say detours will be well marked and all parts of the mall will be accessible.

Lindau is being closed to lower the roadbed 20 feet so an enormous bridge can be built over the street. That bridge, which will be about 167 feet wide and 140 feet long, will act as a plaza for a few years but ultimately will be part of the base of an expected three-story addition to the mall.

"We are working hard to keep things moving smoothly with signs to get people where they need to go," said Bloomington city engineer Shelly Pederson. "We are trying to make it better so as the area grows, there is not severe congestion."

The mall is located in Bloomington's South Loop district, where 65 percent of the city's future development is expected to occur. While much of this spring's construction is centered on Lindau, work over the next two years also will build infrastructure east of the mall to transform an area of parking lots and humdrum office buildings into a mixed-used, walkable area with green space, offices and apartment and condo buildings.

The city hopes that by 2020, the area will have 6,000 residents and 35,000 people working in a neighborhood with four light-rail stations and rail access to the airport.

"This is why transportation improvements are so important," Pederson said. "We need to get products and people to where they need to be."

Last year, office buildings and a warehouse were razed near the mall's northeast corner, opening the way for the eventual extension of Lindau to 30th Avenue S. Utility lines were moved.

The bridge above Lindau will be landscaped and function as a plaza with a horseshoe drive for car drop-offs until mall expansion reaches that area. Even after Lindau reopens to traffic from Hwy. 77 to 24th Avenue in summer 2014, there may be lane closures for landscaping and other work.

Protecting pedestrians

This week, construction is expected to start on a pedestrian bridge over Killebrew Drive on the mall's south side. The bridge, which resembles a skyway, will run from the Radisson Blu hotel's parking ramp to the other side of the street.

The intent is to stop people who try to cross Killebrew Drive, a 10-lane road, on foot. Julie Long, a city civil engineer and manager of the South Loop project, said the bridge will have stairs and an elevator and should improve safety in the area.

"Drivers are leaving a freeway environment and are not expecting pedestrians," she said. Eventually, walls will be put up to stop people from trying to cross the road.

Another big change coming this summer is a "diverging diamond" that will modify the intersection of 34th Avenue and Interstate 494. Construction on that project will start in July.

Two other diverging diamonds are being built in the state but none are open yet. They are structured so that there are no left turns against oncoming traffic.

Construction in the area over three years will cost about $49 million, including $15.45 million from the state and $33.5 million from local sources, including tax-increment financing by the mall.

For more information on the South Loop area and to get updates on traffic changes, go to Bloomington's website.